Report: Islamic State has used chemical weapons 52 times in Iraq and Syria since 2014

The Islamic State has used chemical agents 52 times in Iraq and Syria since 2014, according to a new report published Tuesday.

The report, put out by IHS Markit, a information analytics company, and IHS Conflict Monitor, a subsidiary of IHS that uses open-source information to gather data from war zones, also warned of the extremist group's increasing likelihood of using chemical weapons as it retreats from the city of Mosul.

As Iraq's second-largest city and an ISIS stronghold since June 2014, Mosul has seen heavy fighting in recent weeks as Iraqi and Kurdish troops have advanced from multiple directions in an attempt to retake it. ISIS has used snipers, anti-tank guided missiles and car bombs in an effort to stymie the offensive, but the group has yet to use any conventional chemical weapons as forces enter the city.

Chemical weapons are strictly regulated by international arms treaties.

The Islamic State did, however, set fire to a nearly burnt out sulfur mine roughly 25 miles southeast of Mosul as the campaign to retake the city began in earnest. As the wind shifted, the noxious fumes wafted over nearby U.S. troops and civilians displaced from the city, causing the troops to don gas masks and incapacitating hundreds of the unprotected civilians with nose bleeds, headaches and choking fits.

"As the Islamic State loses ground around Mosul, there is a high risk of the group using chemical weapons to slow down and demoralize advancing enemy forces, and to potentially make an example of - and take revenge on - civilian dissidents within the city," said Columb Strack, senior analyst and head of the IHS Conflict Monitor, in the report.

Since 2014, ISIS has used chemical weapons 19 times around Mosul. However, before the Iraqi offensive on the city, chemical attacks declined, the report said. This is probably because the group's chemical weapons technicians and experts were evacuated to Syria, the report added.